First of all, I'm currently reading the SFML Game Development book, in the first chapter, when movement is introduced, I encountered some problems, I spawn a white circle in the centre of the window, now If i press any directional arrow, the circle keeps going in the other direction till I press it, and then it gets back to normal, and horizontal and vertical ones are seperate.
Example: I start "Game", press up, the circle keeps going down, i hold up, the circle stands still, I release, it keeps going down, I press down, it stops, now it responds normally to both keys, it will happen again with the right and left, it gets fixed after the initial error, but I wish to know how I can remove it
#include <SFML/Graphics.hpp>
using namespace sf;
class Game
{
public:Game();
void run();
private:
void processEvents();
void update(Time);
void render();
void handlePlayerInput(Keyboard::Key,bool);
bool mIsMovingUp, mIsMovingRight, mIsMovingLeft, mIsMovingDown;
float playerSpeed;
Time TimePerFrame;
private:
RenderWindow mWindow;
CircleShape mPlayer;
};
Game::Game():mWindow(VideoMode(640, 480), "SFML Application"),mPlayer(), playerSpeed(20.f), TimePerFrame(seconds(1.f / 60.f))
{
mPlayer.setRadius(20.f);
mPlayer.setPosition(220.f, 220.f);
mPlayer.setFillColor(Color::White);
}
void Game::handlePlayerInput(Keyboard::Key key, bool isPressed)
{
if (key == Keyboard::W || key == Keyboard::Up)
mIsMovingUp = isPressed;
else if (key == Keyboard::S || key == Keyboard::Down)
mIsMovingDown = isPressed;
else if (key == Keyboard::A || key == Keyboard::Left)
mIsMovingLeft = isPressed;
else if (key == Keyboard::D || key == Keyboard::Right)
mIsMovingRight = isPressed;
}
void Game::run()
{
Clock clock;
Time timeSinceLastUpdate = Time::Zero;
while (mWindow.isOpen())
{
processEvents();
timeSinceLastUpdate += clock.restart();
while (timeSinceLastUpdate > TimePerFrame)
{
timeSinceLastUpdate -= TimePerFrame;
processEvents();
update(TimePerFrame);
}
render();
}
}
void Game::processEvents()
{
Event event;
while (mWindow.pollEvent(event))
{
switch (event.type)
{
case Event::KeyPressed:
handlePlayerInput(event.key.code, true);
break;
case sf::Event::KeyReleased:
handlePlayerInput(event.key.code, false);
break;
case sf::Event::Closed:
mWindow.close();
break;
}
}
}
void Game::update(Time deltaTime)
{
Vector2f movement(0.f, 0.f);
if (mIsMovingUp)
movement.y -= playerSpeed;
if (mIsMovingDown)
movement.y += playerSpeed;
if (mIsMovingLeft)
movement.x -= playerSpeed;
if (mIsMovingRight)
movement.x += playerSpeed;
mPlayer.move(movement * deltaTime.asSeconds());
}
void Game::render()
{
mWindow.clear();
mWindow.draw(mPlayer);
mWindow.display();
}
int main()
{
Game game;
game.run();
}
